1. Field of the Invention
The present invention relates to a vehicle transmission control apparatus.
2. Description of the Related Art
Such a vehicle transmission control apparatus is disclosed in, for example, Japanese Patent No. 2959937.
In this transmission control apparatus, a shift map corresponding to the inclination of an uphill is selected on the basis of the uphill determination value calculated on the basis of a difference between an expected acceleration and an actual acceleration. The transmission control apparatus performs a shift-changing operation in accordance with the selected shift map. Therefore, the risk of occurrence of a shift-busy state, in which upshifting and downshifting repeatedly occur while a vehicle climbs an uphill, thereby causing the driver to experience an uncomfortable feeling, can be reduced.
In the above-described transmission control apparatus according to the related art, in the case where a vehicle climbs an uphill while towing a heavy object, such as a trailer, the uphill determination value suddenly decreases if the driver releases an accelerator pedal, as will be described in more detail below in the Description of the Preferred Embodiments section. Therefore, even when a shift map for a steep uphill is to be selected, a shift map for a gentler uphill may be selected instead. In such a case, there is a possibility that the undesirable shift-busy state will occur.